Energy Storage

2. The method according to claim 1 , wherein the validating the one of the candidate charging occasion and the candidate discharging occasion comprises detecting whether the pricing data relating to the candidate charging occasion and the candidate discharging occasion represents the respective lowest or highest price before the later price which validates that candidate occasion, and if not, replacing the candidate charging or discharging occasion by the respective lowest or highest price before the later price which validates that candidate occasion.

3. The method according to claim 1 , wherein the pricing data used by the detecting and validating represents a time average of the pricing data over a predetermined time period.

4. The method according to claim 1 , wherein the validating integrates the cost of electricity consumption against time over a charging cycle to detect the price associated with a charging occasion.

5. The method according to claim 1 , wherein the validating applies a time-varying energy loss relating to a charged energy storage device in dependence upon an elapsed time since the last charging occasion.

6. The method according to claim 1 , further comprising determining whether a first of the occasions should he a charging occasion or a discharging occasion in dependence upon a present charging state of the energy storage device.

7. The method according to claim 6 , wherein the determining comprises comparing a measure of the present charging state with a threshold amount.

8. The method according to claim 7 , further comprising varying the threshold in dependence upon the pricing data.

10. An energy storage apparatus, comprising: the energy storage controller according to claim 9 ; the energy storage device comprising one or more batteries; and an inverter for producing an output voltage higher than the battery voltage.

11. An energy storage apparatus, comprising: the energy storage controller according to claim 9 ; and the energy storage device comprising: one or more batteries; a movable mass having a motor for driving the movable mass; and a generator for generating electrical power from motion of the movable mass.

13. The energy storage controller according to claim 9 , wherein the circuitry is configured to validate the one of the candidate charging occasion and the candidate discharging occasion by detecting whether the pricing data relating to the candidate charging occasion and the candidate discharging occasion represents the respective lowest or highest price before the later price which validates that candidate occasion, and if not, replacing the candidate charging or discharging occasion by the respective lowest or highest price before the later price validates that candidate occasion.

14. The energy storage controller according to claim 9 , wherein the pricing data used represents a time average of the pricing data over a predetermined time period.

15. The energy storage controller according to claim 9 , wherein the circuitry validates by integrating the cost of electricity consumption against time over a charging cycle to detect the price associated with a charging occasion.

16. The energy storage controller according to claim 9 , wherein the circuitry validates by applying a time-varying energy loss relating to charged energy storage device in dependence upon an elapsed time since the last charging occasion.

17. The method according to claim 1 , wherein the energy losses include lost energy released as heat during the charging or the discharging of the energy storage device.

18. The energy storage controller according to claim 9 , wherein the energy losses include lost energy released as heat during the charging or the discharging of the energy storage device.